Tubular bag machine for filling a product

ABSTRACT

The invention relates to a tubular bag machine for filling a product into bags ( 9 ), comprising a vertical filling tube ( 2 ), a transverse sealing unit ( 3 ), a control unit ( 4 ) for controlling the tubular bag machine, and a sensor device ( 5 ) for detecting the product in the filling tube ( 2 ), which is designed to detect the product falling through the filling tube ( 2 ), wherein the sensor device ( 5 ) has a sensor ( 51 ) for emitting electromagnetic waves, and which is connected to the control unit ( 4 ), wherein the electromagnetic waves emitted by the sensor ( 51 ) remain in a detection space (E) which is confined to one region at the filling tube ( 2 ).

BACKGROUND OF THE INVENTION

The present invention relates to a tubular bag machine for filling aproduct.

Vertical tubular bag machines are known in various designs from theprior art. Product elements of a product to be filled are herebydetected by a sensor device in order to ascertain the amount of productfilled into the tubular bag. In so doing, sensors are used which emitelectromagnetic waves, such as, e.g., in the X-ray or microwave range,and are disposed along the vertical fall distance on the outside of thefilling tube. Such a tubular bag machine is, e.g., known from the Germanpatent specification DE 10 2006 013 663 A1. In this case, it isparticularly disadvantageous that different electromagnetic fieldgeometries result as a function of the diameter of the filling tubeused, of the electromagnetic wave length emitted and of the coupling ofthe sensor on the side of the tubular bag machine. As a result, thesensor detects not only a large section of the vertical fall distancebut even possibly detects objects outside of the filling tube.

SUMMARY OF THE INVENTION

The tubular bag machine according to the invention has in contrast theadvantage that a sharp delimitation of the detection region of thesensor is thereby implemented; thus enabling products falling past thesensor to be detected with greatly improved precision. The radiation isconfined to a detection space in the filling tube. According to theinvention, this results from the fact that the tubular bag machinecomprises a vertical filling tube, a transverse sealing unit, a controlunit for controlling the tubular bag machine and a sensor device fordetecting the product in the filling tube, which is designed to detectthe product falling through the filling tube. To this end, the sensordevice comprises a sensor for emitting and detecting electromagneticwaves, said sensor being connected to the control unit. Theelectromagnetic waves emitted by the sensor thereby remain in adetection space which is confined to one region at the filling tube. Asa result, the detection space is for the most part independent of thesensitivity, power output as well as the transmission frequency of thesensor. Cost effective sensors can thus be used because the qualityrequirements, e.g. with regard to antenna characteristics,directionality, side lobes and manufacturing tolerances, aresubstantially lower. In addition, an identical sensor can be used fordifferent diameters of the filling tube.

The detection space is preferably delimited by at least one firstabsorber element and a second absorber element, which are disposed atthe filling tube so as to be axially spaced from each other. By thepositioning of the absorber elements, which are, for example,manufactured from a ferrite/plastic composition or a carbon filledplastic, in the direction of fall above and below the detection space,the electromagnetic waves are prevented from spreading further in thefilling tube and the measurement region of the sensor is therebydelimited in an upward and downward direction. As a result, a volume ofthe detection space can further be defined which is adapted to theelectromagnetic waves used as well as to the nature of the product to befilled. In so doing, a precise detection and an optimized machinecontrol can be achieved.

According to a preferred embodiment of the invention, the two absorberelements are designed to completely run around the filling tube. As aresult, an operationally reliable absorption of the electromagneticradiation is achieved.

In a further preferable manner, the absorber elements are disposed inthe interior of the filling tube, in particular integrated into saidfilling tube. In particular, the absorber elements do not protrude froman inner wall of the filling tube. In so doing, a particularly compactdesign can be achieved which has a uniform diameter and does notobstruct the products falling through the filling tube.

According to a preferred embodiment of the invention, the detectionspace is cylindrical. Optimal reflection properties are thereby createdwhich also permit the use of cost effective sensors without specialquality requirements or manufacturing tolerances for precisely detectingall of the product elements.

An intermediate region is preferably configured between the absorberelements as a metallic reflector for the electromagnetic waves emittedby the sensor. As a result, a homogenous field distribution andtherefore a uniform detection sensitivity is achieved for theelectromagnetic waves spreading between the absorber elements due toreflections.

In addition, the reflector is preferably one piece or embodied so as tobe divided up into a plurality of segments; or the reflector is aninside wall region of the filling tube. Depending on the type ofapplication or the nature of the product to be filled, an operationallyreliable detection of all of the product elements falling through thedetection space can thus be assured. Furthermore, a separate receiver istherefore not required, whereby a cost efficient minimization of thenumber of components results.

According to a preferred embodiment of the invention, a plurality ofabsorber elements is disposed in each case, starting at the detectionspace, in the axial direction of the filling tube. In so doing, anoperationally reliable absorption of the entire electromagneticradiation is variably facilitated for differing electromagnetic waveranges. In addition, sensors having variable sensor frequencies canthereby be used.

The sensor is furthermore preferably disposed in a wall of the fillingtube, preferably flush with an inner wall of the filling tube. In sodoing, a particularly compact design is achieved without impairing theperformance and the sensitivity of the sensor. Moreover, the sensor canbe replaced in a simple manner without a great deal of installation workor costs.

According to a preferred embodiment of the invention, the sensor has adimension in the axial direction of the filling tube, which dimension isequal to or greater than a distance in the absorber elements in theaxial direction. An operationally reliable detection of all of theproduct elements along the entire fall line thereof in the detectionspace is facilitated having larger adjustment tolerances of the sensorantenna.

The filling tube is preferably formed from a plurality of differentmaterials. This allows for a simple production of the filling tube, e.g.by means of a combination of individual parts connected to one anotherin modular design in a time and cost efficient manner.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of the invention is described below in detailwith reference to the accompanying drawings. In the drawings:

FIG. 1 shows a schematic sectional view of a tubular bag machineaccording to a preferred exemplary embodiment of the invention;

FIG. 2 shows a schematic longitudinal sectional view of a filling tubesection comprising a sensor device; and

FIG. 3 shows a schematic sectional view along an intersection line 1-1of FIG. 2.

DETAILED DESCRIPTION

A tubular bag machine for filling a product according to a preferredexemplary embodiment is described below in detail with reference toFIGS. 1 to 3.

FIG. 1 shows a schematic sectional view of a tubular bag machine 1 forfilling a product according to a preferred exemplary embodiment of theinvention. The tubular bag machine 1 comprises a filling funnel 8, inwhich a product to be filled is delivered in portions, in a direction offall A, to a vertical filling tube 2 attached thereto. A packagingmaterial delivered cyclically is formed around the filling tube 2 intoan elongated packaging material tube 7 by means of a forming shoulder 6,said packaging material tube being welded by a longitudinal sealing unit(not depicted here) using a longitudinal sealing seam in thelongitudinal direction. The tubular bag machine 1 further comprises atransverse sealing unit 3 having horizontal first and second sealingjaws 31, 32 which are disposed at an end of the filling tube 2 that isopposite to the filling funnel 8. The transverse sealing unit 3initially seals a foot seam on the packaging material tube 7, which hasbeen molded and cyclically delivered. After a portion of the product hasfallen into said packaging material tube and the filled tube section hasbeen moved downwards, the packaging material tube 7 is sealed by meansof a head seam to form a closed bag 20, wherein the foot seam of thesucceeding packaging is also simultaneously sealed.

In addition, a sensor device 5 disposed in the filling pipe 2 isprovided, said sensor device detecting the product elements 11 of theproduct being filled which fall through the filling tube 2. The sensordevice 5 comprises a sensor 51 which is disposed in a wall 20 of thefilling tube 2 and is connected via a cable 14 to a control unit 4 forcontrolling the tubular bag machine 1, the former being disposed outsideof the filling pipe 2 and above the forming shoulder 6. Provision ishereby made to embed the cable 14 in the wall 20 or to alternativelydesign said cable as flat cable which runs on the inside of the fillingtube 2 and does not impair a flow capacity of the product fallingthrough said filling tube. The sensor 51 is disposed substantially flushwith an inside wall of the filling tube 2.

The sensor 51 emits electromagnetic waves into a cylindrical detectionspace E which is delimited to a region at the filling tube 2 by a firstabsorber element 54 and a second absorber element 55 which are disposedin the direction of fall A above or, respectively, below the sensor 51.

As is illustrated in FIG. 2, the sensor 51 has a dimension B in an axialdirection X-X of the filling tube 2, which dimension is greater than adistance C between the absorber elements 54 and 55. The sensor 51 emitselectromagnetic waves, which are indicated schematically in FIG. 2 bycircular segment type lines L, into the cylindrically shaped detectionspace E.

The electromagnetic waves are reflected by an inside wall region of thefilling tube 2, which is situated between the absorber elements 54, 55and is designed as a metallic reflector 21, and received by the sensor51. Each product element 11 detected in the detection space E causes asignal change in the electromagnetic waves received at the sensor 51,said signal change being transmitted via the cable 14 to the controlunit 4 that is not visible in FIG. 2. The reflector 21 can alsoalternatively be designed so as to be divided into a plurality ofsegments in the circumferential direction.

The first and second absorber elements 54, 55 absorb the electromagneticwaves in the axial direction X-X of the filling tube 20. The absorberelements 54, 55 are designed in a completely circumferential manner inthe interior of the filling tube 2, in particular integrated into saidfilling tube 2, as is illustrated in sectional view at a line ofintersection II-II of FIG. 2 for the second absorber element 55 that isvisible in FIG. 3. A plurality of absorber elements, e.g. havingdifferent absorption properties, can also optionally be respectivelydisposed, starting from the detection space E, in the axial directionX-X of the filling tube 2; or the filling tube 2 can be formed from acorresponding plurality of different materials.

The tubular bag machine 1 according to the invention for a product thushas the advantage that a cylindrical detection space E is providedwithin the filling tube 2, wherein the former is spatially sharplydelimited. Said detection space thus facilitates a significantlyimproved detection of all of the product elements 11 falling through thefilling tube 2, which is for the most part independent of thesensitivity, power output, radiation pattern and transmission frequencyof the sensor 51 as well as the diameter of the filling tube 2. Costeffective sensors having significantly lower quality demands cantherefore be used. In addition, the radiation is confined to thedetection space E in the filling tube 2.

1. A tubular bag machine for filling a product, comprising a verticalfilling tube (2), a transverse sealing unit (3), a control unit (4) forcontrolling the tubular bag machine, and a sensor device (5) fordetecting the product in the filling tube (2), which is designed todetect the product falling through the filling tube (2), wherein thesensor device (5) has a sensor (51) for emitting electromagnetic waves,and which is connected to the control unit (4), wherein theelectromagnetic waves emitted by the sensor (51) remain in a detectionspace (E) which is confined to one region at the filling tube (2). 2.The tubular bag machine according to claim 1, characterized in that thedetection space (E) is delimited by at least one first absorber element(54) and a second absorber element (55) which are axially spaced apartfrom one another at the filling tube (2).
 3. The tubular bag machineaccording to claim 2, characterized in that the two absorber elements(54, 55) at the filling tube (2) are designed in a completelycircumferential manner.
 4. The tubular bag machine according to claim 2,characterized in that the absorber elements (54, 55) are disposed in theinterior of the filling tube (2), in particular arc integrated into thefilling tube (2).
 5. The tubular bag machine according to claim 2,characterized in that the detection space (E) is cylindrical.
 6. Thetubular bag machine according to claim 2, characterized in that anintermediate region between the absorber elements (54, 55) is designedas a metallic reflector (21) for the electromagnetic waves emitted bythe sensor (51).
 7. The tubular bag machine according to claim 6,characterized in that the reflector (21) is designed as one piece. 8.The tubular bag machine according to claim 1, characterized in that aplurality of absorber elements is respectively disposed, starting at thedetection space (E), in an axial direction (X-X) of the filling tube(2).
 9. The tubular bag machine according to claim 1, characterized inthat the sensor (51) is disposed in a wall (20) of the filling tube (2).10. The tubular bag machine according to claim 1, characterized in thatthe filling tube (2) is formed from a plurality of different materials.11. The tubular bag machine according to claim 2, characterized in thatthe absorber elements (54, 55) are integrated into the filling tube (2).12. The tubular bag machine according to claim 6, characterized in thatthe reflector (21) is divided into a plurality of segments.
 13. Thetubular bag machine according to claim 6, characterized in that thereflector (21) is an inside wall region of the filling tube (2).